module: coupled deferred execution
module: coupled deferred execution

This commit removes the optional deferred execution set of classes and
introduces enforced transactional state coupled in the HTML Highlighter
module's `Main` class (1).  Clients must now call `apply` after invoking
any of `add`, `remove`, `enable`, `disable` or `clear`.

Design NOT the author's own.

(1) exported as `HtmlHighlighter`.

Subessware/html-highlighter,dossier/html-highlighter,Subessware/html-highlighter,dossier/html-highlighter,Subessware/html-highlighter,dossier/html-highlighter